Process for producing photographic color images

ABSTRACT

2-equivalent couplers for forming cyan dye images in color photography of the naphthol type and characterized by a sulfonyl or sulfinyl group in the coupling position are provided. Such couplers have the inherent advantages of 2-equivalent color couplers and, additionally, a high degree of reactivity, little or no tendency to produce stains by nonimagewise coupling and have all of the desirable attributes of prior art cyan-forming couplers.

United States Patent 72] inventors Robert J. Pollet Berchem; Raphael K. Van Poucke, Berchem; Arthur Henri De Cat, Mortsel, all of Belgium [2 l Appl. No. 719,243 [22] Filed Apr. 4, I968 [45] Patented Nov. 23, 1971 [73 Assignee Gevaert-Agfa N.V.

Mortsel, Belgium [32] Priority Apr. 1 l, 1967 [33] Great Britain [3 l] 16,456/67 [54] PROCESS FOR PRODUCING PHOTOGRAPHIC COLOR IMAGES 14 Claims, No Drawings 52] US. Cl 96/55, 96/ l 00 51 Int. Cl G03c 7/00, G03c 1/40 50 Field ofSearchJ.

Mees, The Theory of the Photographic Process," Third Edition, page 344, The Macmillan Company, New York, (1966).

Primary Examiner-J. Travis Brown Attorney-Alfred W. Breiner ABSTRACT: 2-equivalent couplers for forming cyan dye images in color photography of the naphthol type and characterized by a sulfonyl or sulfinyl group in the coupling position are provided. Such couplers have the inherent advantages of 2-equivalent color couplers and, additionally, a high degree of reactivity, little or no tendency to produce stains by nonimagewise coupling and have all of the desirable attributes of prior art cyan-forming couplers.

PROCESS FOR PRODUCING PHOTOGRAPHIC COLOR IMAGES This invention relates to photography and particularly to compounds which form dyes on coupling with the oxidized developing agent to produce colored images.

It is known that for the production of a photographic color image in a light-sensitive silver halide emulsion layer the exposed silver halide is developed to a silver image by means of an aromatic primary amino compound in the presence of a color coupler which, by reaction with the oxidized developer, forms a dye on the areas corresponding with the silver image.

In the subtractive three-color photography usually a lightsensitive photographic color material is used comprising a redsensitized, a green-sensitized and a blue-sensitive silver halide emulsion layer wherein on development by means of suitable color couplers, a cyan, a magenta and a yellow dye image are formed respectively.

ln photographic elements for three color photography the cyan-forming couplers are usually phenols or naphthols and present in the red-sensitive layer, the magenta-forming couplers are ordinarily pyrazolones and usually present in the green-sensitive emulsion layer and the yellow-forming couplers are usually compounds containing a methylene group having two carbonyl groups attached to it and are ordinarily present in the blue-sensitive emulsion layer. Sometimes, however, the color couplers are incorporated into the color developing bath.

Color couplers have a coupling position at which the oxidized aromatic primary amino-developing agent is coupled to produce a dye, which is dependent on the nature of the color coupler and of the particular developing agent used. If at the coupling position no substituent is present then for the formation of one molecule of dye, four molecules of exposed silver halide must be developed in order that one molecule of coupler can react with a molecule of oxidized developer. These couplers are referred to as 4-equivalent couplers.

It is known, that if at the coupling position of the coupler a halogen atom e.g. chlorine is attached, coupling still takes place with the production of the same dye as is formed when the reactive coupling group is unsubstituted. ln the coupling reaction the halogen atom is readily displaced and the effect of this displacement is that for the production of 1 molecule of dye there are required the oxidation products resulting from the production of only 2 molecules of silver. Therefor, these couplers are referred to as 2-equivalent couplers.

The foregoing is apparent from the formulas given for the coupling reactions on page 390 of The Theory of the Photographic Process" by C. E. K. Mees, the Mac Millan Company, New York, 1966.

By the use of 2-equivalent couplers it is possible to reduce the cost of making the emulsions since they require for the production of the coupled dye only half the amount of silver halide which is required in the case of 4-equivalent couplers. Moreover, it is possible to improve the quality of the images produced because it is possible to use thinner emulsion layers owing to the fact that less silver halide is necessary and it is known that reducing the thickness of emulsion layers results in improved image definition and resolution. Reduction of emulsion thickness has the further advantage of decreasing the opacity of the emulsion allowing more light to penetrate into an underlying emulsion layer. Thus 2-equivalent couplers are particularly suitable for use in multilayer materials.

Certain of the available 2-equivalent couplers tend to produce more stain than is desired and others do not have the desired coupling reactivity.

According to the present invention a novel class of 2- equivalent couplers for forming cyan dye images in color photography is provided, which couplers are of the naphthol type and are characterized by the presence in the coupling position of a sulfonyl or sulfinyl group corresponding to the formula:

wherein R, represents alkyl including substituted alkyl, aralkyl including substituted aralkyl, aryl including substituted aryl e.g. phenyl substituted by nitro, amino, halogen such as chlorine, alkyl such as methyl, carboxyl, sulfo or a heterocyclic ring system including a substituted heterocyclic ring system, and

n represents 1 or 2.

Apart from having the inherent advantages of 2-equivalent color couplers given above, the 2-equivalent color couplers according to the invention have a high degree of reactivity, have little or no tendency to produce stains by nonimagewise coupling and have all of the desirable features of prior art cyan-forming couplers since it is possible to substitute at the 2 carbon of the naphthol ring of the couplers of the invention the corresponding substituents from any of the prior art cyanforming naphthol couplers; among these desirable features may be mentioned good spectral absorption characteristics, good stability to prolonged exposure to light, heat and humidity, etc. Moreover, photographic silver halide emulsion layers wherein a color image is formed with the color couplers of the invention possess a higher maximum density, gradation and sensitivity than emulsion layers containing the corresponding 4-equivalent couplers.

The couplers of the invention are further characterized in that, upon coupling with oxidized developer to form a dye, they can release substances having a stabilizing, more particularly a development-inhibiting, action. lndeed, each coupler molecule upon reaction with oxidized developer and the formation of a cyan dye molecule, releases the sulfonyl or sulfinyl group attached to'the coupling position of the coupler, as a sulfinic acid or a (hypothetical) sulfenic acid, which can undergo further reactions resulting in the formation of more stable products. It is known that certain sulfmic acid derivatives e.g. arylsulphinic acids have antifogging properties and are used as antioxidants in photographic emulsions (see P. Glafkides Photographic Chemistry Vol. I, Fountain Press, London, l958,p. 378 and the above book by C. E. K. Mees, p. 344) The development-inhibiting compounds released from the couplers on development locally inhibit development of the silver halide crystals with the result that improvement in grain results. This effect would be due to the fact that development takes place at a number of development centers in each grain causing growth of a corresponding number of silver grains. Upon fixation of the emulsion the undeveloped portion of the original silver halide grain is removed leaving a number of small silver halide grains rather than a single large silver grain. Since these antifoggants become only effective upon development they do not disadvantageously influence the sensitivity of the emulsion as most of the common antifoggants do.

Another interesting feature of the color couplers according to the invention is that the group released upon reaction with oxidized developer contains a solubilizing group so that it can be washed out of the material. The photographic importance of this feature lies in the fact that it is possible to introduce into the sulfonyl or sulfinyl group an azo group which imparts color to the color coupler. On color development the colored color coupler is left unaffected in the unexposed areas of the layer whereas in the exposed areas a cyan dye is formed as well as an azo dye released from said color coupler, which contains a solubilizing group and thus can be washed away. This chemical system affords a means for correcting automatically the undesirable side absorptions of the cyan dye produced (it is supposed that the cyan dye image absorbs only red light but, undesirably it also absorbs green and blue light). For instance, an emulsion layer can be prepared which contains an orange-colored color coupler that yields a cyan dye on color development, which orange color is obtained by the introduction of an appropriate azo group in the sulfonyl or sulfinyl group of the color couplers according to the invention. Upon color development the layer contains a cyan dye image as well as an orange dye image called mask image of opposite gradation and absorbing light in the blue and green regions of the visible spectrum. So upon printing the mask image dissimulates in fact the side absorptions in the cyan dye image, which means that by correctly exposing the positive color material through a color negative, masked in this way, positive color images are produced with a more true color reproduction.

According to a preferred feature of the invention the cyanforming color couplers correspond to the following general formula:

CONHR;

wherein n and R have the same significance as above, and

R represents any of the radicals used in the prior art cyanforming l-hydroxyl-Z-napthamide color couplers including such radicals as alkyl, substituted alkyl, aryl, substituted aryl, a heterocyclic radical and a substituted heterocyclic radical. Some typical examples of radicals for R are hexadecyl, ethyl, sulfoethyl, phenyl, phenyl substituted by halogen such as chlorine, bromine, fluorine, by a sulfo group, a carboxyl group, a fluorosulfonyl group, by alkyl such as methyl, by alkoxy such as methoxy, hexadecyloxy, by alkylthio such as octadecylthio by disubstituted amino such as dimethylamino, by sulfamoyl by phenyl, by aralkyl such as benzyl etc.

Preferably at least one of R, and R contains a radical rendering the molecule fast to diffusion. Further details about said radical rendering the coupler fast to diffusion are given hereinafter.

The following is a nonlimitative list of structural formulas of color couplers corresponding to the above general formula and suitable for use according to the present invention.

oil

lOH

XII. (HI

XIII.

The color couplers of use according to the present invention i and corresponding to the above general formula can be prepared by oxidation in acid medium with hydrogen peroxide of the corresponding l-hydroxy-2-napthamides carrying in the 1 4-position an R,S-group wherein R has the same sig-i nificance as above. it is also possible particularly for the preparation of color couplers carrying in the 4-position the 4- position R,SO to oxidize the l-hydroxy-Z-napthoic acid phenyl ester carrying in the 4-position the thioether group and i then to melt the oxidized product with the appropriate amine. i

The l-hydroxy-Z-napthamides carrying in the 4-position the i said R,S-group are prepared by treating the appropriatei parent compound comprising no such R,S- substituent in! an inert solvent such as carbon tetrachloride, l,2-! dichloroethane, chloroform etc. with the appropriate sulphenyl chloride (R,SC1) prepared in the same solvent from the, corresponding thiol or disulfide and chlorine.

The 1-hydroxy-2-napthoic acid phenyl ester carrying in the; 4-position the said R,--S- group can be prepared in an analogous way from the unsubstituted l-hydroxy-2-napthoic acid phenyl ester and the appropriate sulphenyl chloride.

Descriptions and preparations used to make the parent 1- hydroxy-2-napthamides can be found in the literature and are 1 well known to those skilled in the art and thus need not re-l peated here.

The colored color couplers of the invention i.e. those containing in the sulfonyl or sulfinyl group an azo group can be prepared as illustrated hereinafter.

The following preparations illustrate more particularly how the color couplers can be prepared.

Preparation 1: Compound Vl a. N-hexadecyl-1-hydroxy-4-phenylthio-2-napthanide 62 g. of N-hexadecyl-l-hydroxy-Z-napthamide and 22 g. of benzenesulphenyl chloride were stirred in 800 ml. of chloroform. After having been kept overnight, the mixture was refluxed for 4 hours and the chloroform was removed by evaporation. The residue was recrystallized from ethanol. Yield: 71.5 g. Melting point: C.

b. N-hexadecyll -hydroxy-4-phenylsulfinyl- 39 g. of N-hexadecyl-l-hydroxy-4-phenylthio-2-naphthamide were stirred in ml. of acetic acid whereupon 17. l g. of 30 percent hydrogen peroxide were added. The mixture was heated to 60 C. whereby all solids dissolved. Heating was stopped and stirring was continued for 1 hour. The mixture was poured into water and the precipitate formed was filtered by suction. The product was recrystallized from ethanol. Yield: 38 g. Melting point: 96 C.

Preparation 2: Compound VII a. l-hydroxy-4-phenylthio-2-napthoic acid phenyl ester 132 g. of l-hydroxy-2-napthoic acid phenyl ester and 75 g. of benzene sulphenyl chloride were stirred in 750 ml. of chloroform. After having been kept overnight, the mixture was refluxed for 3 hours and the chloroform was distilled off. The residue was boiled in ethanol and the warm ethanol was filtered off by suction. The product was recrystallized from acetonitrile. Yield: 100 g. Melting point: 171 C.

b. lacid phenyl ester 95 g. of 1-hydroxy-4-phenylthio-2-napthoic acid phenyl ester were stirred in 750 ml. of acetic acid whereupon 175 g. of 30 percent hydrogen peroxide were added. The mixture was stirred for 90 min. at 90 C. After cooling the precipitate formed was filtered by suction and dried. Yield: 89 g. Melting point: 184 C.

c. N-4-hexadecyloxphenyl 1 -hydroxy-4-phenylsulphonyl-2- napthamide 13.3 g. of p-hexadecyloxy-aniline and 16.2 g. of l-hydroxy- 4-phenylsulphonyl-2-napthoic acid phenyl ester were melted at 170 C. After 30 min. the phenol formed was distilled off under reduced pressure and the residue was recrystallized from ethylene glycol monomethyl ether. Yield: point: g. Melting point 134 C.

Preparation 3: Compound [X a. N-( 2-hexadecyloxyphenyl)- l -hydroxy-4-phenylthio-2- napthamide 200 g. of N-(2-hexadecyloxyphenyl)-l-hydroxy-Z-napthamide and 56 g. of benzenesulphenyl chloride were stirred in 800 ml. of chloroform. After having been kept overnight, the mixture was refluxed for 4 hours and the chloroform distilled off. The residue was recrystallized from a mixture of ethylene glycol monoethyl ether and ethanol. Yield: 185 g. Melting point: 90 C.

b. N-( 2-hexadecyloxyphenyl l -hydroxy-4-phenylsulphonyl- Z-naphthamide 30.6 g. of N-(2-hexadecyloxyphenyl)4-phenylthio-2- napthamide were stirred in 200 ml. of acetic acid whereupon 34 g. of 30 percent hydrogen peroxide were added. The mix- 65 ture was stirred for 1 hour at 90 C. and then poured into water. The precipitate formed was filtered by suction and recrystallized from a mixture of ethylene glycol monomethyl ether and ethanol. Yield: 22 g. Melting point: 106 C. Preparation 4: Compound XVll acid phenyl ester dissolved in 2 liters of chloroform. After having been kept overnight, the mixture was refluxed for 4 hours and the chloroform distilled off. The residue was boiled in ethanol and the product filtered by suction. The product was recrystallized from ethylene glycol monomethyl ether. Yield: 415 g. Melting point: 144 C.

b. lhydroxy-4pchlorophenylsulfonyl-2-napthoic acid phenyl ester 152 g. of lhydroxy-4-p-chlorophenylsulphonyl-2-napthoic acid phenyl ester were stirred in 750 ml. of acetic acid whereupon 325 g. of 30 percent hydrogen peroxide were added. The mixture was refluxed for 4 hours. After cooling the precipitate formed was filtered by suction, boiled in ethanol, filtered again and dried. Yield: 154 g. Melting point: 216 C.

c. N-hexadecyl-lhydroxy-4-p-chlorophenylsulfonyl-2- napthamide 22 g. of lhydroxy-4-p-ch1orophenylsulfonyl-2napthoic acid phenyl ester and 12.1 g. of hexadecylamine were melted whereupon, after 30 min., the phenol formed was distilled off under reduced pressure. The residue was recrystallized from ethanol. Yield: 22 g. Melting point: 95 C.

Preparation 5 compound XlX a. N-hexadecyl-1hydroxy-4-nitrophenylthiO-Z-napthamide 51 g. of bis-p-nitrophenyl disulfide were dissolved in 500 ml. of chloroform whereupon 12 g. of chlorine were introduced while cooling. The excess of chlorine was removed by introducing nitrogen.

The solution formed was added with stirring to a solution of 141.2 g. of N-hexadecyl-l-hydroxy-2naphthamide in 700 ml. of chloroform. The reaction mixture was refluxed for 2 hours and the residue, after having been filtered off was recrystallized from methanol. Yield: 162 g. Melting point: 102 C.

b. N-hexadecyll hydroxy-4-p-nitrophenylsulfonyl-Z-napthamide 160 g. of the compound described in step (a) was stirred in 800 ml. of acetic acid and heated on a boiling water-bath. To the solution obtained 145 ml. of 50 percent hydrogen peroxide were added in 30 min. After the addition the mixture was stirred for 4 hours with heating on a boiling water-bath. The mixture was then left standing overnight and the precipitate formed was filtered by suction and dried at 70 C. Yield: 80 g. Melting point: 90 C.

c. N-hexadecyl- 1 hydroxy-4-paminophenylsulfonyl-2- napthamide 62.9 g. of the above nitro compound were dissolved in a mixture of ethylene glycol monomethyl ether and dimethyl formamide (2:1) together with 3 ml. of Raney nickel. The whole was diluted to 500 ml. whereupon a hydrogen pressure of 1,500 p.s.i. was applied at 80 C.

After 2 hours the reduction was complete and the Raney nickel was filtered off whereupon 1 liter of methanol was added and the mixture cooled inice. The precipitate formed was filtered off. Yield: 25 g. Melting point: 1 19 C.

d. N-hexadecyl-l-hydroxy-4-p-(p, N,N-dimethylaminophenylazo) phenylsulfonyl-Z-napthamide In a 400 ml. flask were placed 5.6 g. (0.01 mole) of the above amino compound and 100 ml. of n-propanol. The mixture was heated with stirring till the compound dissolved.

whereupon 5.7 g. (0.03 mole) of p-toluene sulfonic acid-1- water were added and the mixture was cooled to 20 C.

1.52 g. of isoamyl nitrite were added and the reaction mixture was stirred for l hour whereupon 0.1 g. of urea was.

added. The solution was filtered and then added at a temperature of -5 C. to a solution of 1.21 g. of N,N-dimethylaniline in 5 ml. of N sodium hydroxide and 50 ml. of ethanol.

The mixture was stirred for 2 hours and 25 ml. of water were added thereto. By acidification with 5 ml. of acetic acid an orange precipitate formed. The precipitate was filtered by suction and recrystallized from ethylene glycol monomethyl ether.

According to one feature of the present invention there is provided a process of color development which includes developing a reducible silver salt image with an aromatic primary amino developing agent in the presence of a color coupler as defined above.

According to a further feature of the invention, there is provided a photographic emulsion suitable for forming a colored photographic image when coated on a support, which comprises a light-sensitive silver halide in a hydrophilic colloid binder, such as gelatin, in which is incorporated a color coupler as defined above.

The invention includes as new compounds the color couplers as defined above, and as new compositions: a color developer comprising an aromatic primary amino-developing agent and a dispersible or soluble color coupler as defined above as well as a photographic element comprising a support bearing at least one layer of a photographic emulsion as defined above.

The 2-equivalent couplers of the present invention may be of the diffusible-type i.e. of the kind, the solubility of which is sufficient to enable them to be usefully incorporated in aqueous developing baths to color-develop light-sensitive elements (see e.g. couplers l to 1V above). They may also be of the nondiffusible type" i.e. of the kind that is suitable of being incorporated in photographic hydrophilic colloid-silver halide emulsion layers where they remain during color development (see e.g. couplers V to XVlll above).

When the dye image formed on color development is to be used in situ e.g. as, or as part of, a color transparency or color print, the coupler must be one that gives a substantially nondiffusing dye (see e.g. couplers V to XIV and XVI, XVll and XVlll).

When the dye image is to be used for image transfer processes it should be diffusible but capable of being mor- Y danted or fixed in the image-receiving sheet. For this purpose a coupler is selected which will produce this type of dye i.e. a nondifiusible coupler of which the group rendering the coupler fast to diffusion is present in the sulfonyl or sulfinyl group which is released upon color development (see e.g. coupler XV).

For manufacturing an appropriate photographic multilayer color material containing color couplers for each color separation image in the differently optically sensitized silver halide emulsion layers the color couplers must be of the nondiffusible type. This object can be accomplished e.g. by the use of a sufficiently water-soluble color coupler comprising an organic radical which is sufiiciently large to prevent the color coupler from diffusing in the hydrophilic silver halide emulsion layer, or by the utilization of a lipophilic color coupler, which e.g. in dissolved state in a high-boiling organic solvent, is dispersed in the silver halide emulsion layer.

For the purpose of rendering the color coupler fast to diffusion, radical R, and/or radical R in the above general formula can be or can contain a radical rendering the molecule fast to diffusion e.g. the group XD wherein D is preferably an aliphatic radical containing from five to 20 carbon atoms in straight line and X stands for a chemical bond, an oxygen atom, a sulfur atom, a NHCO-group, a NHSO -group, a SU N(R)-group wherein R stands for hydrogen or alkyl, a N(alkyl)-group or a sulphonyl group. sulfonyl The nondiffusing color couplers of the present invention can be incorporated into the photographic material according to any technique known by those skilled in the art for incorporating photographic ingredients into colloid compositions. For instance the water-soluble color couplers e.g. those containing one or more sulfo or carboxyl groups (in acid or salt form) can be dissolved in water if necessary in the presence of alkali and the water-insoluble color couplers can be dissolved in the appropriate water-miscible or water-immiscible organic solvents or mixtures thereof whereupon the solution obtained is dispersed, if necessary in the presence of a wetting agent in a hydrophilic colloid composition forming or forming part of the binding agent of the colloid layer e.g. a silver halide emulsion layer. The hydrophilic colloid composition may of course comprise in addition to the colloid carrier e.g. gelatin all other sorts of ingredients. When the color coupler is intended Effie I incorporated into a light-sensitive silver halide emulsion layer the solution of said color coupler need not necessarily be dispersed directly in the melted silver halide emulsion. Said solution may advantageously be first dispersed in an aqueous nonlight-sensitive hydrophilic colloid solution whereupon the resultant mixture, if necessary after the removal of the solvents, is intimately mixed with the light-sensitive silver halide emulsion just before coating. For more details about particularly suitable dispersing techniques according to which the color couplers according to the invention can be incorporated into a hydrophilic colloid layer of a photographic material there can be referred to published Dutch patent applications 6,516,423 filed Dec. 16, 1965, 6,600,098 filed Jan. 5, 1966, 6,600,628 filed Jan. 18, 1966, 6,600,099 filed Jan. 5, 1966, 6,516,424 filed Dec. 16, 1965, 6,714,713 filed Oct. 30, 1967 all by Gevaert-Agfa N.V., to U.S. Pat. No. 2,304,940 of Leopold D. Mannes and Leopold Godowsky, Jr. issued Dec. 15, 1942 and to United Kingdom patent specification 791,219 filed Nov. 9, 1955 by Kodak Ltd. It is evident that the nondiffusing color couplers may also be added to the composition of a nonlight-sensitive layer which is in water-permeable relationship with the light-sensitive silver halide emulsion.

The couplers according to'the above general formula may be used in conjunction with various kinds of photographic emulsions. Various silver salts may be used as the sensitive salt, such as silver bromide, silver iodide, silver chloride, or

mixed silver halides, such as silver chlorobromide, silver bromoiodide and silver chlorobromoiodide. The couplers can be used in emulsions of the mixed packet type, such as described in U.S. Pat. No. 2,698,794 of Leopold Godowsky issued Jan. 4, 1955 or emulsions of the mixed-grain type as described in U.S. Pat. No. 2,592,243 of Burt H. Carroll and Wesley T. Hanson, Jr. issued Apr. 8, 1952. The color couplers can be used with emulsions wherein latent images are formed predominantly on the surface of the silver halide crystal, or

with emulsions wherein latent images are formed predominantly inside the silver halide crystal.

The hydrophilic colloid used as the vehicle for the silver halide may be, for example, gelatin, colloidal albumin, zein, casein, a cellulose derivative, a synthetic hydrophilic colloid such as polyvinylalcohol, etc. If desired, compatible mixtures of two or more of these colloids may be employed for dispersing the silver halide.

The light-sensitive silver halide emulsions of use in the preparation of a photographic material according to the present invention may be chemically as well as optically sensitized. They may be chemically sensitized by effecting the ripening in the presence of small amounts of sulfur-containing compounds such as allyl thiocyanate, allyl thiourea, sodium thiosulphate etc. The emulsions may also be sensitized by means of reductors for instance tin compounds as described in French patent specification 1,146,955 filed Apr. 1 l, 1956 by Gevaert Photo-Producten NV. and in the Belgian patent specification 568,687 filed June 18, 1958 by Gevaert Photo- Producten N.V., imino-amino methane sulfinic acid compounds as described in British patent specification 789,823 filed Apr. 29, 1955 by Gevaert Photo-Producten NV. and

small amounts of noble metal compounds such as of gold,

platinum, palladium, iridium, ruthenium and rhodium. They may be optically sensitized by means of cyanine and merocyanine dyes.

The said emulsions may also comprise compounds which sensitize the emulsions by development acceleration for example compounds of the polyoxyalkylene type such as alkylene oxide condensation products as described among others in U.S. Pat. Nos. 2,531,832 of William Alexander Stanton issued Nov. 28, 1950, and 2,533,990 of Ralph Kingsley Blake issued Dec. 12, 1950 and in United Kingdom patents 920,637 filed May 7, 1959,940,( )51 filed Nov. 1, 1961, 945,340 filed Oct. 23, 1961. all by Gevaert Photo-Producten NV. and 991,608 filed June 14, 1961 by Kodak Ltd. and in Belgian patent specification 6 48,710 filed June 2, 1964 by Gevaert Photo- Producten NV. and onium derivatives of amino-N-oxides as described in published Dutch patent application 6,612,269 filed Aug. 31, 1966 by Gevaert-Agfa N.V. Further, the emulsions may be stabilized with heterocyclic nitrogen-containing thioxo compounds such as benzothiazoline-Z-thione and 1- phenyl-2-tetrazoline-5-thione and compounds of the hydroxytriazolopyrimidine type. They can also be stabilized with mer- 10 cury compounds such as the mercury compounds described in Belgian patent specifications 524,121 filed Nov. 7, 1953 by Kodak SA. and 677,337 filed Mar. 4, 1966 by Gevaert-Agfa N.V., published Dutch patent application 6,715,932 filed Nov. 23, 1967 by Gevaert-Agfa NV. and in U.S. Pat. specification 3,179,520 of Yoshio Miura, Akira Kumai and Yosuke Nakajima issued Apr. 20, 1965.

The light-sensitive emulsions may also comprise all other kinds of ingredients such as plasticizers, hardening agents,

wetting agents, etc.

The nondiffusing cyan color formers described in the present invention are usually incorporated into a red-sensitized silver halide emulsion for forming one of the differently sensitized silver halide emulsion layers of a photographic multilayer color material. Such photographic multilayer color material usually comprises a support, a red-sensitized silver halide emulsion layer with a cyan-forming color coupler, a green-sensitized silver halide emulsion layer with a magentaforming color coupler and a blue-sensitive silver halide emulsion layer with a yellow-forming color coupler.

The emulsions can be coated on a wide variety of photographic emulsion supports. Typical supports include cellulose ester film, polyvinylacetal film, polystyrene film, polyethylene terephthalate film, and related films of resinous materials, as

well as paper and glass.

Elements made for image transfer processing may use a separate reception sheet which is contacted with the light-sensitive layer during its development or the reception layer may be an integral part of the light-sensitive element. Any of the support materials mentioned above may be used for a separate reception sheet. For photographic color diffusion transfer processes in general there can be referred to U.S. Pat. specification 3,227,550 of Keith E. Whitmore and Paul M. Mader issued Jan. 4, 1966.

For the production of photographic color images according to the present invention an exposed silver halide emulsion layer is developed preferably with an aromatic primary amine developing substance in the presence of a color coupler as defined above.

Suitable developing agents are aromatic compounds, such as p-phenylene diamine, N,N-dialkyl-p-phenylenediamines,

such as N ,N-diethyl-p-phenylenediamine, and derivatives such as N,N-dialkyl-N'-sulphomethyl-p-phenylenediamines phenylenediamines and N,N-dialkyl-N'-carboxymethyl-p-phenylenediamines.

The following examples illustrate the use of the cyan-form- 6() ing color couplers according to the present invention.

EXAMPLE 1 0.01 mole of the color coupler of formula [X is dissolved in 50 ml. of ethylacetate. The solution obtained is dispersed at 6 5 50 C. by means of a high-speed stirrer into 200 ml. of a 3 percent aqueous solution of gelatin. The ethyl acetate is then removed under reduced pressure and the gel is concentrated to 176 g.

The gel obtained is dispersed in a gelatino silver bromoiodide emulsion (2.3 mole percent of iodide) which contains triacetate support.

After having been dried the coating was exposed for 1/20 sec. through a continuous wedge with constant 0.30 and then developed for 8 min. at C. in a developing bath of the folwater to make 1 The developed material is treated for 2 min. at l820 C. in an intennediate bath comprising g. of sodium sulfate in 1 liter of water.

The material is rinsed for 15 min. with water and treated in a bleach bath of the following composition:

horax 20 g. anhydrous potassium bromide 15 g. anhydrous sodium bisulfate 4.2 g. potassium hcxacyunofcrratc (I11) 100 g.

EXAMPLE 2 Three silver bromoiodide emulsions A, B and C are prepared as described in example 1 with the difference that color coupler 1X is replaced by 0.01 mole of the color coupler corresponding to the formula:

R @joomemmmwm 0.01 mole of the color coupler V and 0.01 mole of the color coupler V] respectively.

The three emulsions A, B and C are coated on a subbed cellulose triacetate support and dried.

The respective materials A, B and C comprise per sq.m.:

A: an amount of silver halide equivalent to approximately 1.3 g. ofsilver nitrate, approximately 0.95 g. ofcolor coupler and approximately 5.2 g. of gelatin.

B: an amount of silver halide equivalent to approximately 1.1 g. ofsilver nitrate, approximately 1.10 g. of color coupler and approximately 5 .2 g. of gelatin.

C. an amount of silver halide equivalent to approximately 1.2 g. ofsilver nitrate, approximately 1.15 g. ofcolor coupler and approximately 5.2 g. of gelatin.

(AD- when the material, before processing, has been stored for 3 days in an atmosphere of 37 tive humidity. The results attained,

are listed in the following table.

Processing occurs as described in example 1.

C. and 94 percent of relawhich are self-explanatory Table Material Max. Grad- Relative AD, AD, A dens. atiun speed nm.

A 0.81 0.96 -42% 24% 670 B 1.54 1.00 162 6% 9% 672 C 2.69 1.62 229 091' 7% 672 EXAMPLE 3 1.04 g. of color coupler XIX was dissolved in 16 ml. of ethanol and 2 ml. of 2N sodium hydroxide. The solution was admixed with 29.3 g. of a conventional silver bromoiodide emulsion comprising per kg. an amount of silver halide corresponding with 55 g. of silver nitrate and about 70 g. of gelatin whereupon 48 g. of a 5 percent aqueous solution of gelatin, 25 g. of water, 0.2 ml. of 5-methyl-7-hydroxy-striazolo 1.5-a]pyrimidine and 2 ml. ofsaponine are added.

After adjustment of the pH and dilution to 144 ml. the emulsion was coated on a subbed cellulose triacetate support and dried.

The material was further processed as described in example 1.

On the exposed areas a cyan dyestuff image is formed whereas on the unexposed areas the orange-colored color coupler remains and forms a mask image.

EXAMPLE 4 ln a manner similar to that illustrated in example 1 above molecularly equivalent amounts of other color couplers useful in practicing our invention incorporated in the same photographic emulsion followed by identical exposure and processing, produced cyan wedge images having the Amax values shown in the following table.

color coupler A...

V" 692 X 688 XI 710 an aralkyl group, an aryl group CONHR 13 wherein n stands for l or 2,

R, stands for an alkyl group, an aralkyl group, an aryl group or n heterocycle,

R, stands for an alkyl group, an aryl group or a heterocycle.

3. A process according to claim I in which the R, group is a phenyl group.

4. A process according to claim 1, wherein the R, group is substituted by a color conferring azo grouping.

5. A process according to claim 1, wherein the cyan dyestuff formed on color development of the said photographic element by reaction of said color coupler with the oxidized aromatic primary amino-developing agent is diffusible.

6. A process according to claim 1, wherein the cyan dyestuff formed on color development of the said emulsion layer by reaction of said color coupler with the oxidized aromatic primary amino-developing agent is nondiffusible.

7. A process according to claim 1 in which the cyan-forming color coupler corresponds to the formula:

CONHR;

wherein n stands for l or 2,

R, stands for an alkyl group, an aralkyl group, an aryl group or a heterocycle,

R, stands for an alkyl group, an aryl group or a heterocycle, and wherein at least one of R and R is or comprises a radical rendering the molecule nondifiusible corresponding to the formula X-D wherein D is an aliphatic radical containing from five to carbon atoms in straight line and X stands for a chemical bond, an oxygen atom, a sulfur atom, a NHCO-group a NHSO -group, a SO N(R)-group wherein R stands for hydrogen or alkyl, N(alkyl)-group or a sulfonyl group.

8. A process according to claim 1 wherein said color coupler is present in a light-sensitive silver halide emulsion layer and/or colloid layer in water-permeable relationship with said emulsion layer of the said photographic element.

9. A process according to claim 1, wherein the said color coupler is present in the said developer composition.

10. A photographic element comprising at least one lightsensitive silver halide emulsion layer and a cyan-forming color coupler of the naphthol type carrying in the coupling position a sulfonyl or sulfinyl group of the formula:

wherein n represents l or 2, and R stands foran alkyl group, an aralkyl group, an aryl group or a heterocycle. 11. A photographic element according to claim 10, wherein the said cyan-forming color coupler corresponds to the formula:

CONHR;

wherein :1 stands for l or 2,

R, stands for an alkyl group, an aralkyl group, an aryl group or a heterocycle,

R stands for an alkyl group, an aryl group or a heterocycle, and wherein at least one of R, and R is or comprises a radical rendering the molecule nondiffusible corresponding to the formula -X--D wherein D is an aliphatic radical containing from five to 20 carbon atoms in straight line and X stands for a chemical bond, an oxygen atom, a sulfur atom, a NHCO-group, a NHSO -group, a SO N(R)-group wherein R stands for hydrogen or alkyl, a N(alkyl)-group or a sulfonyl group. 

2. A process according to claim 1, wherein the said cyan-forming color coupler corresponds to the formula:
 3. A process according to claim 1 in which the R1 group is a phenyl group.
 4. A process according to claim 1, wherein the R1 group is substituted by a color-conferring azo grouping.
 5. A process according to claim 1, wherein the cyan dyestuff formed on color development of the said photographic element by reaction of said color coupler with the oxidized aromatic primary amino-developing agent is diffusible.
 6. A process according to claim 1, wherein the cyan dyestuff formed on color development of the said emulsion layer by reaction of said color coupler with the oxidized aromatic primary amino-developing agent is nondiffusible.
 7. A process according to claim 1 in which the cyan-forming color coupler corresponds to the formula:
 8. A process according to claim 1 wherein said color coupler is present in a light-sensitive silver halide emulsion layer and/or colloid layer in water-permeable relationship with said emulsion layer of the said photographic element.
 9. A process according to claim 1, wherein the said color coupler is present in the said developer composition.
 10. A photographic element comprising at least one light-sensitive silver halide emulsion layer and a cyan-forming color coupler of the naphthol type carrying in the coupling position a sulfonyl or sulfinyl group of the formula: R1-S(O)n-wherein n represents 1 or 2, and R1 stands for an alkyl group, an aralkyl group, an aryl group or a heterocycle.
 11. A photographic element according to claim 10, wherein the said cyan-forming color coupler corresponds to the formula:
 12. A photographic element according to claim 10, wherein the R1 group is a phenyl group.
 13. A photographic element according to claim 10, wherein the R1 group is substituted by a color-conferring azo grouping.
 14. A photographic element according to claim 10, wherein the said cyan-forming color couplers corresponds to the formula: 